Unless otherwise indicated herein, approaches described in this section are not prior art to the claims listed below and are not admitted as prior art by inclusion in this section.
There are various well-developed and well-defined cellular communications technologies in telecommunications that enable wireless communications using mobile terminals, or user equipment (UE). For example, the Global System for Mobile communications (GSM) is a well-defined and commonly used communications system, which uses time division multiple access (TDMA) technology, which is a multiplex access scheme for digital radio, to send voice, video, data, and signaling information (such as a dialed telephone number) between mobile phones and cell sites. The CDMA2000 is a hybrid mobile communications 2.5G/3G (generation) technology standard that uses code division multiple access (CDMA) technology. The UMTS (Universal Mobile Telecommunications System) is a 3G mobile communications system, which provides an enhanced range of multimedia services over the GSM system. The Long-Term Evolution (LTE), as well as its derivatives such as LTE-Advanced and LTE-Advanced Pro, is a standard for high-speed wireless communication for mobile phones and data terminals. In addition, there are some newly developed next generation communication technologies such as 5th Generation (5G), New Radio (NR), Internet of Things (IoT) and Narrow Band Internet of Things (NB-IoT). These communication technologies are developed for higher speed transmission and serving for huge number of devices including machine type devices.
In some communication systems, in order to perform a non-access stratum (NAS) signaling procedure, the UE may need to establish a NAS signaling connection with the network apparatus. When the NAS signaling procedure is finished, it is supposed that there is no other data needed for transmission. Then, the UE should be waiting for the network apparatus to release the signaling connection or the UE should locally release the signaling connection. However, during the period of waiting for signaling connection release, there may be a mobile-terminated (MT) circuit-switched (CS) call coming. It is not clear how the UE should deal with the incoming MT CS call since the signaling connection is going to be released.
Accordingly, it is important for the UE to properly deal with the conflict between the incoming MT CS call and the release of the signaling connection. Therefore, in developing communication systems, it is needed to provide proper mechanisms for arbitrating such conflict.